Global Range: (1000-5000 square km (about 400-2000 square miles)) Recently separated taxonomically from Ariolimax columbianus, this species occurs from Tuolomne Co., Monterey Co., the eastern shore of San Francisco bay (including Alameda, Sacramento, Mendocino, Marin, and San Francisco Co.) and the City of San Francisco (Leonard et al., 2007). It is also expected to occur in Shasta Co. (Roth and Sadeghian, 2006).